Sunnybrook Health Sciences Centre

About: Sunnybrook Health Sciences Centre is a healthcare organization based out in Toronto, Ontario, Canada. It is known for research contribution in the topics: Population & Medicine. The organization has 7689 authors who have published 15236 publications receiving 523019 citations. The organization is also known as: Sunnybrook.

Persistence of serum and saliva antibody responses to SARS-CoV-2 spike antigens in COVID-19 patients.

Abstract: While the antibody response to SARS-CoV-2 has been extensively studied in blood, relatively little is known about the antibody response in saliva and its relationship to systemic antibody levels. Here, we profiled by enzyme-linked immunosorbent assays (ELISAs) IgG, IgA and IgM responses to the SARS-CoV-2 spike protein (full length trimer) and its receptor-binding domain (RBD) in serum and saliva of acute and convalescent patients with laboratory-diagnosed COVID-19 ranging from 3-115 days post-symptom onset (PSO), compared to negative controls. Anti-SARS-CoV-2 antibody responses were readily detected in serum and saliva, with peak IgG levels attained by 16-30 days PSO. Longitudinal analysis revealed that anti-SARS-CoV-2 IgA and IgM antibodies rapidly decayed, while IgG antibodies remained relatively stable up to 105 days PSO in both biofluids. Lastly, IgG, IgM and to a lesser extent IgA responses to spike and RBD in the serum positively correlated with matched saliva samples. This study confirms that serum and saliva IgG antibodies to SARS-CoV-2 are maintained in the majority of COVID-19 patients for at least 3 months PSO. IgG responses in saliva may serve as a surrogate measure of systemic immunity to SARS-CoV-2 based on their correlation with serum IgG responses.

Prediction of probable Alzheimer's disease in memory-impaired patients: A prospective longitudinal study

Abstract: We determined whether a battery of neuropsychological tests could predict who would develop Alzheimer's disease (AD) in a group of 123 memory-impaired nondemented patients. Patients were followed longitudinally for 2 years with a research battery of neuropsychological tests. After 2 years, 29 developed probable AD, and 94 did not develop dementia. We used logistic regression analyses to examine the classification accuracy of subjects' performance at entry to the study on the research battery. The logistic regression model was significant with an accuracy of 89%, sensitivity of 76%, and specificity of 94%. Two tests contributed significantly to this model: the delayed recall from the Rey Auditory Verbal Learning Test and the Mental Control subtest of the Wechsler Memory Scale. These two tests alone produced the same accuracy, sensitivity, and specificity as the larger model. These results demonstrate that probable AD can be predicted with a high degree of accuracy and with a relatively brief battery of neuropsychological tests.